Internal combustion engine with scavenging air compressor



Feb. 22, 1944. J. OLSSON EIAL INTERNAL COMBUSTION ENGINE WITH SCAVENGING AIR COMPRESSOR Filed Jan. 31, 1942 r hm m m a n m J iflwwneys.

Patented Feb. 22, 1944 INTERNAL COMBUSTION ENGINE WITH -SCAVENGING AIR COMPRESSOR Johannes Olsson and John Richard Stalblad, Goteborg, Sweden, asslgnors to Aktiebolaget Giitaverken, Goteborg, Sweden, a corporation of Sweden Application January 31, 1942, Serial No. 429,120 In Sweden April 23, 1941 8 Claims. (Cl. 123-74) The present invention relates to single acting two stroke internal combustion engines with reciprocating working pistons and a compression chamber for scavenging and charging air at one side of one or more working pistons of the engine which may naturally have any number of working cylinders.

One object of the invention is to provide such an arrangement of the compressors necessary for an effective scavenging of the cylinders that the length and/or width of the motor is not materially afiected thereby.

Previously, one or more compressor cylinders or other compressors used to be provided in line with the motor cylinders, or one or more compressors adapted to produce the total scavenging and charging air quantity were disposed at one side of the motor.

We, however, prefer to provide sidewise of the longitudinal center plane of a motor of the type set forth one or more air compressors adapted to compress air into a scavenging air chamber, into which one or more of the working pistons are also arranged to compress air. The invention results in a reduction of the length of the' motor as compared with the first mentioned old design mentioned hereinabove and of the width of the engine as compared with the last mentioned old design.

On the accompanying drawing one embodiment of a single acting two stroke internal combustion motor according to the invention is illustrated by way of example.

Fig. 1 is a vertical cross sectional view, and

Fig. 2 a vertical longitudinal section of one cylinder and the pertaining crank mechanism of an internal combustion motor according to the invention.

Fig. 3 is a horizontal section of the scavenging air casing of said motor according to line IIIIII in Fig. 1. I

The motor illustrated inthe drawing is a single acting two stroke motor of the cross head type provided with uniflow scavenging of the working cylinder from the piston towards the cylinder head, but the invention is not limited to this type of motors and may also be employed in connection with trunk motors or motors of any other type with any scavenging system within the scope of the claims. The illustrated motor is provided with a bearing frame I forming the lower half of the crank case, and an intermediate frame 2 forming the upper half of the crank case. In the bearing frame a crank shaft 3 is mounted, said crank shaft being by means of connecting rods 4 and piston rods 5 connected with working pistons 6 movable in the working cylinders 1. The piston rods 5 are connected with cross heads 8 guided in the usual way on guides 9. Naturally, the motor may have any number of cylinders, one of which only is illustrated in the drawing. The illustrated working cylinder 1 is provided with inlet ports in for scavenging and charging air and an exhaust valve I2 disposed in the cylinder head II. The valve I2 is carried by a cross bar l3 actuated by tie rods l4 and levers l5 mounted in the crank case and actuated by cams It provided on the crank shaft. Naturally, the valve and the valve motion may be of any well known construction and, for instance, separate shafts driven from the crank shaft 3 of the engine may be provided for actuation of the valve, and the valve may, for instance, have the form of a piston with opposed motion to the working piston and controlling ports in the top of the cylinder and connected with the crank shaft of the engine or a separate shaft in a known manner.

For the production of the necessary scavengin and charging air a compression chamber I1 is provided at the under side of the working piston 6. Said compression chamber is separated from the crank case by means of a horizontal wall l8, through which the piston rod 5 and the tie rods l4 are carried in suitable packings. The compression chamber I1 is provided with automatic intake valves I9, through which air is drawn into the compression chamber from around the motor when the piston 6 moves upwards. In order to enable the necessary quantity of scavenging and charging air for the working cylinder to be drawn into the compression chamber l1 and compressed therein an auxiliary compressor cylinder 20 having less diameter than the working cylinder is disposed at the s de of the working cylinder with parallel cylinder axis. A piston 2| is provided in said auxiliary compressor cylinder and connected by means of a piston rod 22 with an arm 23 extending from the cross head. However, the auxiliary piston might also be driven from a separate shaft. The lower end of the compressor cylinder 20 communicates with the compression chamber ll whereas the upper end is provided with a separate compression chamber 24 and separate in take valves 25. The compression chamber I1 is connected with a scavenging air casing 21 enclosing the cylinders l, 20 over automatic pressure valves 28. Said scavenging air casing forms a scavenging air chamber 28. The compression chamber 24 is connected with the scavenging air chamber 28 over a pressure valve 29 of any conventional type. The compressor cylinder and the two pressure valves 28 are disposed on in each corner of the rectangular scavenging air casing 21, the fourth corner oi! which is occupied by a device 30 for supplying cooling medium to the working piston 6 through the cross head pin and the piston rod. Instead of one or more of the automatic valves i9, 25, 26 and 29 positively operated valves might have been provided.

The arrangement of the auxiliary compression cylinder 20, the pressure valves 26 and the cooling medium supply device 30 for the working piston results in an eflicient utilization of the available space within the scavenging air casings 21. The

compressed air necessary for scavenging and charging the working cylinder is formed, as described hereinabove, partly in the compression chamber l1 upon the downward movement of the pistons 6, 2|, said air being introduced over the pressure valves 28 into the scavenging air chambers, and partly in the compression chamber 24 upon the upward movement of the piston 21. Each working cylinder according to the invention is provided with a separate compression chamber l'l formed between the walls I8 and the bottoms oi the scavenging air casings 21. but the scavenging air casings 21 of different cylinders in a multiple cylinder engine may preferably communicate and form a continuous scavenging air conduit. For this purpose Openings may be provided in the walls between adjacent scavenging air casings. Some working cylinders in multiple cylinder engines may naturally be carried out without the auxiliary compressor cylinder.

In order to enable the use of a comparatively short working piston 5 and to prevent air from the scavenging air chamber from flowing through the inlet ports ill to the compression chamber II when the openings Ill are uncovered at the under side of the working piston a sleeve 3| is provided at the outside of the inlet ports l0, said sleeve being connected with the tie rods ll so that the sleeve follows the movements of the tie rods. When the working piston 6 is so long that the ports in are never uncovered at the under side of the piston said sleeve may naturally be dispensed with. 32, 33 and 34 indicate packings for the tie rods II in the top and bottom of the scavenging air casings and in the wall I8. 35 and 36 indicate packings for the piston rods 5 and 22, respectively, in the wall [8.

The internal combustion engine above described and illustrated in the drawing should only be considered as an example and the invention may naturally be carried out in several difl'erent ways within the scope of the claims. The auxiliary compressor might for instance be carried out as a blower or a centrifugal fan disposed at the side of the center line of the motor and driven thereby.

What we claim is:

1. In a single acting internal combustion engine, a working cylinder, a reciprocating working piston movable in said working cylinder, a compression chamber for scavenging and charging air at one side of said working piston, a, scavenging air chamber communicating with said compression chamber and said working cylinder, a reciprocating compressor disposed sidewise of the longitudinal center plane of said engine arranged to compress air into said scavenging 'air chamber. a reciprocating piston in said compressor, a crank shaft, a crank mechanism for transmitting motion from the working piston to said crank shalt comprising a piston rod. a cross head and a connecting rod connecting said cross head with the crank shaft, and means connecting said cross head with said compressor piston.

2. In a single acting internal combustion engine, a. working cylinder, a reciprocating working piston movable in said working cylinder, a substantially square casing surrounding the working cylinder and forming a scavenging and charging air chamber, a compressor cylinder disposed sidewise oi the longitudinal center plane of said engine in one corner of said square casing, a

compression chamber for scavenging and charging air at one side or said working piston, automatic pressure valves in two other corners of said square casing arranged to control the communication between said compression chamber and the chamber formed by the square casing, and a conduit for supplying cooling medium to the working piston disposed in the fourth corner of said square casing.

3. In a single acting two-stroke internal combustion engine, a working cylinder, a reciprocating working piston movable in said working cylinder, a crank case, a crank shaft in said case, a crank mechanism for transmitting motion from said working piston to said crank shaft, 9. compression chamber communicating with the working cylinder for scavenging and charging air, said compression chamber being disposed on the crank shaft side of the working piston, a scavenging air chamber communicating with said working cylinder, an auxiliary air compressor cylinder disposed to one side of said compression chamber and having a. compression piston reciprocably mounted therein, said auxiliary compressor cylinder communicating with the compression chamber and arranged to coact with the working cylinder to force air from the compression chamber into said scavenging chamber upon the actuation oi said pistons. means separating the compression chamber from the crank case and the scavenging chamber, valve controlled means for communicating the compression chamber with the scavenging air chamber, and means operatively congifting the auxiliary piston to the crank mecha- 4. In a single acting two-stroke internal combustion engine, a working cylinder, a reciprocating working piston movable in said working cylinder, a crank case, a crank shaft in said case, a crank mechanism for transmitting motion from said working piston to said crank shait, a compression chamber communicating with the working cylinder for scavenging and charging air,

.said compression chamber being disposed on the crank shalt side of the working piston, a scavenging air chamber communicating with said working cylinder, an auxiliary air compressor cylinder disposed to one side of said compression chamber and having a compression piston reciprocably mounted therein, said auxiliary compressor cylinder communicating with the compression cham ber and arranged to coact with the working cylinder to force air from the compression chamber into said scavenging chamber upon the actuation of said pistons, means separating the compression chamber from the crank case and the scavenging chamber, valve controlled means for communicating the compression chamber with the scavenging air chamber, said scavenging chamber enclosing said working cylinder, and said auxiliary compressor cylinder, and means operatively connecting the auxiliary piston to the crank mechanism.

5. In a single acting two-stroke internal combustion engine, a working cylinder, a reciprocating working piston movable in said working cylinder, a crank case, a crank shaft in said case, a crank mechanism for transmitting motion from said working piston to said crank shaft, a compression chamber communicating with the working cylinder for scavenging and charging air, said compression chamber being disposed on the crank shaft side of the working piston, a scavenging air chamber communicating with said working cylinder, an auxiliary air compressor cylinder disposed to one side of said compression chamber and having a compression piston reciprocably mounted thereimsaid auxiliary compressor cylinder communicating at one end with the air compression chamber and arranged to coact with the working cylinder to force air from the compression chamber into said scavenging chamber upon the actuation of said pistons, means separating the compression chamber from the crank case and the scavenging chamber, valve controlled means for communicating the compression chamber with the scavenging air chamber, a second compres-.-

sion chamber communicating with the opposite end oi said auxiliary compressor cylinder, and

valve means for controlling communication of said second compression chamber with said scavenging chamber.

6. In a single acting two-stroke internal combustion engine, a working cylinder, a reciprocating working piston movablein said working cylinder, a crank mechanism for transmitting motion from said working piston to said crank shaft, a compression chamber communicating with the working cylinder for scavenging and charging air, said compression chamber being disposed on the crank shaft side of the working piston, a scavenging air chamber communicating with said working cylinder, an auxiliary air compressor cylinder disposed to one side or said compression chamber and having a compression piston reciprocably mounted therein, said auxiliary compressorcylinder communicating with the air compression chamber and arranged to coact with the working cylinder to force air from the compression chamber into said scavenging chamber upon the actuation. of said pistons, means separating the compression chamber from the crank case, valve controlled ber with the scavenging air chamber, a conduit communicating the compressor chamber with the atmosphere, valve means for controlling the flow of air through said conduit, and means operatively connecting the auxiliary piston to the crank mechanism.

7. In a single acting two-stroke internal combustion engine, a working cylinder, a reciprocating working piston movabl in said working cylinder, a crank case, a crank shaft in said case, a

crank mechanism for transmitting motion from said working piston to said crank shaft, a compression chamber communicating with the working cylinder for scavenging and charging air, said compression chamber being disposed on the crank shaft side of the working piston, a scavenging air chamber communicating'with said working cylinder. means separating the compressin chamber from the crank case and the scavenging chamber, valve controlled means for communicating the compression chamber with the scavenging air chamber, an auxiliary air compressor cylinder disposed sidewise of the longitudinal center plane of said engine and having a compression piston reciprocably mounted the'recompressor cylinder, a scavenging air chamber communicating with said compression chamber and the working cylinder, said scavenging chamber being in the form of a substantially square casing and said compressor cylinder being disposed in a comer of said square casing, and a compressor piston in said compressor cylinder,

, said working piston and said compressor piston being arranged to compress air in said compression chamber and into the scavenging air chamber.

JOHANNES OLSSON.

JOHN RICHARD STAL'BLAD.

means for communicating the compression cham- 

